Sewer construction



Feb. 11, 1930. R B, TUFTS I 1,746,566

SEWER CONSTRUCTION Filed Aug. 3l, 1927 MMW www ,Patented Feb. 11, 1930 UNITED STATES PATENT OFFICE i` SEWER CONSTRUCTION Application filed August 31, 1927. Serial No. 216,626.

Apointed out in the appended Claims.

In the drawing, Figure l is a perspectiv view of a portion of a sewer constructed according to the present invention;

Figure 2 is an enlarged transverse section of the same;

Figure 3 is an enlarged detail perspective view of one of the joints in the side walls seen in Fig. l;

j Figures 4 and 5 are plan views showing other-forms of joints;

Figure 6 is a detail elevation, and

Figure 7 is a section showing a variation in the joint between the side andthe bottom of the sewer.

In carrying out the invention, I provide a plurality of precast slabs l of reenforcedconcrete which are employed to form the sides of j the sewer, and are preferably provided in their side edges with grooves 2 adapted to register when the slabs are set up edge to edge. A recess or channel is thus formed into which grout, indicated at 3, is poured so as to key the adjacent slabs together and seal the joints against leakage of the matter flowing through the sewer. Each slab yis provided on one face with a projecting ledge l at an intermediate point in its height for a purpose which will presently appear, it being noted that the under surface of the ledge is at a right angle `to the face of the slab while the upper surface of the ledge is inclined and merges into the face ofthe slab. While I have shown the grooves 2 as terminating short of the lower ends of the slabs,` it will be understood that they may Open through the slab end.

In building a sewer according to the present invention, I first excavate along the line the sewer is to follow and approximately to the ditch. more Vaccurately placed so that thinner slabs the desired depth. I then force into the soil, at the two sides of the ditch, rows of the slabs l to such depth that their lower ends will be below the subgrade 5 of the sewer. The grout 3 may be poured as the successive slabs are 55 placed so that it may set while subsequent Operations are being performed. When two i rows of slabs have been properly positioned to form the sides of the proposed sewer, they are braced apart by jacks or other devices now commonly employed for simi- `lar purposes and excavating then continued to the subgrade 5, whereupon plastic concrete is poured to cover the bottom ofthe excavation and form a monolithic iioor for the sewer, as shown at 6. It will be understood that metallic reenforcing elements may be laid in the floor as the concrete is poured and-it will be noted the floor is formed of such thickness that it abuts the under surfaces ofthe projections. 4f which, consequently, resist upward movment of the floor from pressure below while the floor resists downward movement of the sides. Afterthe floor has set, suitable falseworkis arranged at the top of the sides and concrete is then poured to form the monolithic top or roof 7, it being noted that ribs or shoul- Y ders 8 are formed on the under side of the roof to abut the side slabs and brace the side walls against Collapse from pressureof the surrounding earth. As the roof sets, the falsework is withdrawn and the spaces at the sides of and over the sewer are filled in the usual manner. 3

` The slabs 1 are molded and permitted to set 85 before being `placed in position and may be castjat a central plant and shipped to the point of use, and, being thus produced under factory conditions can be more Cheap-ly and uniformly made than could be done in the field While contending with mud and water in The reenforcements can also be may be used. The'joints between the slabs are made sand and water tight and the sides are so firmly anchored and braced that even a soft wet earth is held against sliding into the ditch.

I'Vhile I have particularly described the slabs as constructed with mating grooves 2, wo

other constructions may be used such as the tongue and groove arrangement shown at 9 in Fig. 4. The edges of the slabs may abut squarely as shown at l0 in Fig. 5 but greater care will then be required to properly seal the joints. Instead of the projections 4, the slabs may have sockets l1 formed therein, asin Fig. 6, so that when the floor is poured it will be automatically keyed to the sides, as indicated at 12 in Fig. 7.

Having fully described my invention what I claim as new and desire to secure by Letters- Patent, is

1. A sewer consisting'of sides each composedr of'a plurality of preformed slabs set edge to edge with their lower ends embedded in the ground and the meeting edges sealed, a monolithic floor formed between the sides, and a monolithic roof formed over and carried by the sides.

2. A sewer consisting of sides each composed of preformed slabs of concrete set on end and edge to edge with their lower ends embedded in the ground and their meeting edges sealed, a monolithic cementitious floor formed between the sides and' interlocked therewith, and a. monolithic cementitious roof formed over and carried bv and interlocked with the sides.

3. A sewer composed of sides each consisting of preformed concrete slabs set edge to edge with their lower ends embedded in the ground and 'their meeting edges sealed and provided above their lower ends with lateral projections, a monolithic floor vformed between the sides and abutting the under surfaces of said projections, and a monolithic roof cast on and carried by the sides.

4. The improvement in sewer construction which consists in forcing preformed concrete slabs into the ground in two rows along the line of the sewer to form the sewer side walls, sealing the joints between the slabs, pouring a monolithic cementitious floor between the rows of slabs at a level above the lower ends thereof, the floor uniting with the sides and pouring ay monolithic cementitious roof at and across the upper ends of the slabs.

In testimony whereof, I have signed this specification.

ROBERT B. TUFTS. 

